Manufacturers of telecommunications processing system devices utilize isolated or integrated grounding schemes to comply with Bellcore. Telecom grounding schemes isolate Frame/Chassis/Safety ground from power ground.
Computer systems and peripherals have traditionally used a single common logic and chassis ground. Thus, all logic components and the chassis enclosing the logic components are connected to a common ground. Chassis components also include the cases of peripheral devices such as tape drives and CD-ROM drives. Therefore, a transient voltage on the device chassis may enter the internal logic components as the transient voltage travels to the single integrated logic and chassis ground. The transient voltage can cause system interruption and damage. A transient voltage such as ESD commonly occurs with devices requiring human interaction. The human body has an electrostatic potential which may discharge upon touching the device. This discharge can be up to 15,000 volts applied directly to the device causing a transient voltage spike which will follow the path of least resistance to a ground. If the electrostatic discharge or any other transient surge occurs on a computer device, such as a CD-ROM drive or a tape drive, the voltage spike follows the path of least resistance to the single common logic and chassis ground. This path could flow through logic components which could be interrupted or damaged due to the voltage spike.
Manufacturers of telecommunications processing devices and systems desire to use computer peripherals in the design of their systems. However, this presents a grounding problem since computer peripherals use a common logic and chassis ground. Some manufacturers of telecommunications processing systems mount computer peripherals in their systems, isolating the computer peripheral from the host system frame using some form of non-conducting isolators. This maintains the separation of the host system logic and frame grounds. However, if the computer peripheral requires human interaction, a transient voltage spike may occur on the computer peripheral. Therefore, the resulting voltage spike would travel through the computer peripheral chassis to the host system logic ground since the computer peripheral's common integrated logic and chassis ground is attached to the host system logic ground. Thus, the voltage spike would enter the host system logic ground which could result in the voltage spike entering logic components thereby causing interruptions or damages to those components.
Due to the aforementioned problems, it is desirable to provide a ground isolation technique that allows for the implementation of computer peripheral devices in a telecommunications system.